Hang Si
Research Group: Numerical Mathematics and Scientific Computing Weierstrass Institute for Applied Analysis and Stochastics (WIAS) Mohrenstr. 39 10117 Berlin, Germany Tel: +49(0) 30 20372 446 Fax: +49(0) 30 2044975 si(at)wias-berlin.de |

I'm a scientific staff member of the Weierstrass Institute for Applied Analysis and Stochastics (WIAS) in the research group of Numerical Mathematics and Scientific Computing. My work is supported under the research project pdelib of WIAS.

The goal of my work is to develope efficient algorithms to automatically generate meshes from arbitrary geometry. It is motivated by solving partial differential equations using numerical methods such as finite element and finite volume methods. I focus on three-dimensional tetrahedral mesh generation. We're developing algorithms to efficiently generate tetrahedral meshes satisfying the Delaunay criterion, which have many nice properties which are important for efficient numerical schemes. We're developing techniques to construct constrained Delaunay tetrahedralizations, quality conforming Delaunay tetrahedralizations for three-dimensional geometries with arbitrarily complicated shapes.

I'm also writing a computer program, TetGen, which is used to implement state-of-the-art methods and algorithms for constructing Delaunay tetrahedralizations and quality tetrahedral meshes. It is one of the best ways to connect "methods" and "results". On the other hand, to provide a robust and efficient meshing tool for solving practical problems in engineering is also very meaningful.

- H. Si.
*TetGen, a Delaunay-based quality tetrahedral mesh generator*. ACM Trans. Math. Softw.,**41**(2):11:1--11:36, February 2015. - J. R. Shewchuk and H. Si.
*Higher-Quality Tetrahedral Mesh Generation for Domains with Small Angles by Constrained Delaunay Refinement*. In Proceedings of the Thirtieth Annual Symposium on Computational Geometry, SOCG 2014, pages 290--299, New York, NY, USA, 2014. ACM. - H. Si and J. R. Shewchuk.
*Incrementally constructing and updating constrained delaunay tetrahedralizations with finite-precision coordinates*. Engineering with Computers,**30**(2):253--269, 2014. [pdf] - H. Si, K. Gärtner,
*3D boundary recovery by constrained Delaunay tetrahedralization*. Int. J. Numer. Meth. Engrg.**85**: 1341--1364, 2011. - H. Si, J. Fuhrmann, K. Gärtner,
*Boundary conforming Delaunay mesh generation*. Comput. Math. Phys.**50**(1):38--53, 2010. - H. Si,
*Constrained Delaunay tetrahedral mesh generation and refinement*. Finite elements in Analysis and Design,**46**(1-2):33--46, 2010. - F. Drechsler, C.H. Wolters, T. Dirkes, H. Si, L. Grasedyck,
*A full subtraction approach for finite element method based source analysis constrained Delaunay tetrahedralization*, NeuroImage,**46**:1055--1065, 2009. - H. Si,
*An analysis of Shewchuk's Delaunay refinement algorithm*, In Proc. 18th International Meshing Roundtable, 2009. [pdf] - H. Si,
*Adaptive tetrahedral mesh generation by constrained Delaunay refinement*, Int. J. Numer. Meth. Engrg.**75**: 856--880, 2008.

**Corrections**: The Lemma 3.3.2 and and the Theorem 3.3.4 in my
Ph.D thesis are
wrong. The correct versions are found in the paper "An analysis of Shewchuk's Delaunay refinement
algorithm, In Proc. 18th International Meshing Roundtable, 2009."

**TetView** is
a small graphic program used to visualize tetrahedral meshes and
piecewise linear complexes. It directly shows the input and output
objects (in files) of TetGen on screen. It also has many features for
understanding and analysing the viewing objects. It dumps screen
contents in high quality encapsulated postscript format. The
executable file (on Unix/Linux platforms) is freely available.

Hang Si